ClearAll;
$DefaultFont = {"Times-Roman",10};
Needs["Statistics`DataManipulation`"];
Needs["Graphics`Graphics`"];
wheat = {{0,0}, {5,6}, {10,11}, {15,15}, {25,18}, 
		 {30,16}, {35,14}, {40,10}, {45,6}, {51,0}};
maize = {{12,0}, {15,9}, {20,20}, {25,29}, 
		 {30,35}, {35,38}, {45,30}, {50,7}, {51,0}};
w0[T_]:= T(T+17)(51-T)(5025 - 127 T + T^2);
m0[T_]:= T(T-12)(51-T)(1884 - 71 T + T^2);
approxw[T_] = Fit[wheat,{w0[T]},T];
approxm[T_] = Fit[maize,{m0[T]},T];
s = Abs[FindMinimum[-approxm[T],{T,37,37.1}][[1]]];
wheatscaled = {{0,0}, {5,6/s}, {10,11/s}, {15,15/s}, {25,18/s}, 
		 	   {30,16/s}, {35,14/s}, {40,10/s}, {45,6/s}, {51,0}};
maizescaled = {{12,0}, {15,9/s}, {20,20/s}, {25,29/s}, 
		 	   {30,35/s}, {35,38/s}, {45,30/s}, {50,7/s}, {51,0}};
appw[T_] = approxw[T]/s;
appm[T_] = approxm[T]/s;
FindMinimum[-appw[T],{T,25}]
FindMinimum[-appm[T],{T,35}]